1. Field of the Invention
The present invention relates to an electrical heating plate structure, and more particularly to an electrical heating plate structure including an electrically conducting plate having multiple heat emitting sections, wherein radial cross-sectional areas of each of the multiple heat emitting sections are different from each other, thereby capable of controlling a temperature distribution of each region of the electrical heating plate structure.
2. Description of the Related Art
A first conventional thin-plate type electrical heating plate 1 in accordance with the prior art shown in FIG. 1 comprises an insulating plate 2, and a continuous winding circuit 3 mounted on the insulating plate 2. The circuit 3 is made of metallic material such as copper having a determined resistance, so that when the current passes through the circuit 3, a heat energy may be produced by the resistance of the metallic material of the circuit 3. Thus, the conventional thin-plate type electrical heating plate 1 may function as a heating source which may provide a heat energy to evaporate the water and remove the moist or mist deposited on a surface such as the windshield window of the car.
In general, each section of the circuit 3 has a constant cross-sectional area, thereby producing a constant heat energy. However, the heat transfer effect of the central region of the circuit 3 is smaller than that of the peripheral region of the circuit 3, whereby the heat adjacent to the central region of the circuit 3 is easily accumulated, so that the instantaneous temperature of the central region of the circuit 3 is much greater than that of the peripheral region of the circuit 3, thereby forming difference of temperature on the surface of the electrical heating plate 1. Thus, when the electrical heating plate 1 is applied on the surface of the windshield window of the car, the windshield window easily produces a crack due to the difference of temperature on the surface of the electrical heating plate 1, thereby greatly decreasing the utility of the conventional thin-plate type electrical heating plate 1.
A second conventional thin-plate type electrical heating plate 1A in accordance with the prior art shown in FIG. 2 comprises a serially arranged circuit 3A. Similarly, each section of the circuit 3A has a constant cross-sectional area, thereby producing a constant heat energy.
A third conventional thin-plate type electrical heating plate 1B in accordance with the prior art shown in FIG. 3 comprises a parallel arranged circuit 3B. Similarly, each section of the circuit 3B has a constant cross-sectional area, thereby producing a constant heat energy.
The closest prior art of which the applicant is aware is disclosed in U.S. Pat. No. 5,928,549 to Hitzigrath, entitled xe2x80x9cETCHED FOIL HEATER FOR LOW VOLTAGE APPLICATIONS REQUIRING UNIFORM HEATINGxe2x80x9d.
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional electrical heating plate.
The primary objective of the present invention is to provide an electrical heating plate structure including an electrically conducting plate having multiple heat emitting sections, wherein the radial cross-sectional areas of each of the multiple heat emitting sections are different from each other, thereby capable of controlling a temperature distribution of each region of the electrical heating plate structure.
In accordance with the present invention, there is provided an electrical heating plate structure, comprising:
an insulating plate; and
at least one electrically conducting plate mounted on the insulating plate;
wherein, the at least one electrically conducting plate includes at least two heat emitting sections, each of the at least two heat emitting sections has different radial widths, so that each of the at least two heat emitting sections has radial cross-sectional areas different from each other, thereby capable of controlling a temperature distribution of each region of the electrical heating plate structure.
Preferably, each of the multiple heat emitting sections has a radial width that is gradually increased from two ends of the heat emitting section toward a mediate portion of the heat emitting section.
Preferably, the radial width of the mediate portion of each of the heat emitting sections is gradually increased from two sides of the insulating plate toward a central portion of the insulating plate, so that each region of the insulating plate has an uniform temperature distribution.
Preferably, two sides of each of the heat emitting sections are formed with symmetric arcuate shapes.
Preferably, the electrical heating plate structure comprises a plurality of independent electrically conducting plates mounted on the insulating plate, thereby providing a large heating area.
Preferably, the radial width of each of the heat emitting sections is gradually increased and gradually decreased in a staggered manner, so that each of the two heat emitting sections may have a symmetric corrugated shape, and wider zones of each of the heat emitting sections may produce a heat smaller than that produced by narrower zones of each of the two heat emitting sections.
Preferably, the heat emitting sections are in parallel with each other, and are connected with each other in a serial manner.
Preferably, the heat emitting sections are in parallel with each other, and are connected with each other in a parallel manner.
Preferably, the heat emitting sections are connected by connecting sections.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
FIG. 1 is a top plan view of a first conventional thin-plate type electrical heating plate in accordance with the prior art;
FIG. 2 is a top plan view of a second conventional thin-plate type electrical heating plate in accordance with the prior art;
FIG. 3 is a top plan view of a third conventional thin-plate type electrical heating plate in accordance with the prior art;
FIG. 4 is a top plan view of an electrical heating plate structure in accordance with a first embodiment of the present invention;
FIG. 5 is a top plan view of an electrical heating plate structure in accordance with a second embodiment of the present invention;
FIG. 6 is a top plan view of an electrical heating plate structure in accordance with a third embodiment of the present invention; and
FIG. 7 is a top plan view of an electrical heating plate structure in accordance with a fourth embodiment of the present invention.